2-Amino-4,6-dimethoxypyrimidine and its derivatives are a group of compounds which are useful as intermediates for various fine chemicals such as biologically active substances, like drugs and pesticides as well as important intermediates for sulfonylurea herbicides described in JP-A-59-122488, JP-A-61-210084 and JP-A-60-208977.
2-Amino-4,5-dichloro-6-methoxypyrimidine is useful, for example, for producing phenylaminopyrimidine compounds described in JP-A-60-51177 and JP-A-61-15877.
As a method for producing 2-amino-4,6-dimethoxypyrimidine, many methods have been known. For example, JP-B-1-211411 discloses a production method by reacting bisimidate obtained from malononitrile with cyanogenchloride. And JP-A-64-16770 discloses a method for producing 2-amino-4,6-dimethoxypyrimidine by reacting 2-amino-4,6-dihydroxypyrimidine with phosphorous oxychloride in the presence of an organic base to prepare 2-amino-4,6-dichloropyrimidine (J. Amer. Chem. Soc., vol. 73, page 3011 (1951)), followed by methoxylation with a metal hydroxide and methanol.
On the other hand, as a method for producing 2-amino-5-chloro-4,6-dimethoxypyrimidine, a method to chlorinate 2-amino-4,6-dimethoxypyrimidine has been known as described in J. Chem. Soc. Perkin Trans. 1, page 375 (1975).
However, with the conventional methods, various types of by-products are generated with large quantities, and improvement is therefore required. And, 2-amino-4,5-dichloro-6-methoxypyrimidine and methods for its production have not been known at all.